A surgical mouth gag (MG) is a retraction device which is insertable into the oral cavity, and is used for surgical procedures of the oral cavity and upper larynges/pharynges in order to provide added accessibility thereto and to keep the mouth open as widely as possible, while retracting the tongue and cheeks from the operation field. MG must be capable of being safely and simply inserted into, and removed from, the oral cavity, a feature which has particular utility during emergency conditions; It provides free access to the operation field by safely and effectively retracting away all the oral cavity's structures such as tongue, maxilla, mandible and cheeks; It is configured to protect, without interference with artificial ventilation airway-devices, such as intra-tracheal tubes or laryngeal masks; Its components do not obstruct the vision of a surgeon and do not interfere in any way with surgical procedures in the oral cavity associated with instruments, devices or systems needed for such surgical procedures; and, it provides illumination for the dark recesses of the surgical field.
Prior art mouth gags comprise means for keeping the jaws ajar and for pressing the tongue away from the oral cavity, and some also comprise lateral retraction arms that retract lateral mouth commissures and cheeks from the oral cavity.
A prior art MG, which is commonly referred to as a Dingman mouth gag and which has been widely used by surgeons for over 70 years, is illustrated in FIG. 1. This prior art MG, which is generally designated by numeral 10, comprises substantially planar frame 5 larger than the maximal mouth aperture, lateral retraction arms 7 which pivot and rotate about a corresponding side rod 9 of the frame, for urging the cheeks away from the oral cavity, laterally displaceable along the frame's upper arm and secured by locking joint 23 teeth blades 11 for contacting the upper teeth or maxilla, and tongue blade 15 and tongue blade shaft 16, the latter being slidable in holder 18 so that tongue blade 15 may be displaced with respect to lower portion 4 of the frame. Latch 21 is used to secure shaft 16 to holder 18 and key 23 is used to set the angular position of a retraction arm 7 to the corresponding side rod 9. Tongue blade 15 is fitted over a ventilation tube (not shown), which is introducible to the trachea of a patient, by means of open region 14 formed in tongue blade 14, such that the latter overlies, and is contact with the ventilation tube.
The Dingman mouth gag, which is the most advanced of all prior art mouth gags and which allows retraction to all directions, suffers from the following drawbacks:
Engagement: Considerable dexterity and skill in manipulating the MG are needed in order to introduce it into the mouth, engage the lower jaw and the tongue without moving the ventilation tube, to engage the upper jaw, retain and retract the jaws to an open position, and to urge the tongue and cheeks away from the oral cavity, particularly since the tongue blade 15 and retraction arms 7 freely move in different directions when released. All these operations should be executed without moving the centrally positioned ventilation tube and without pinching soft tissues such as the tongue and lips. At times, due to the difficulty in manipulating the various components of the MG, misalignment results. Consequently, for example, the tongue blade loses contact with the tongue, parts of the tongue protrude between the tongue blade and the lower mandible alveoli, the ventilation tube can be displaced or pinched and occluded, the teeth blades need to be repositioned, and the MG needed to be urgently removed from the oral cavity and reinserted therein after proper ventilation has been established.
Removal: The removal of the MG from the oral cavity is potentially hazardous as the entire structure with all its retracting arms should be pulled out as one and the ventilation tube is liable to become imbedded in swollen oral tissue or adhere to the tongue blade by desiccated secretions or coagulated blood and be accidentally removed together with the MG.
During a removal procedure, the ventilation tube is liable to be displaced, thereby endangering the life of the patient. At times, an emergency removal procedure is needed, such as a result of an anesthesia-related complication, and difficulty in manipulating the MG is liable to lead to additional medical problems, and even to death. For example, a relatively high moment needs to be applied to key 23 of retraction arm 23, from the inner cheek. The cumbersome removal procedure generally requires several minutes.
Individual anatomical variations: Due to individual anatomical variations, the MG components need to be individually set and adjusted for each patient and the existing devices and their parts are difficult or in some cases impossible to manipulate.
The lower jaw/tongue complex: In order to accommodate the anatomical variations associated with the relative dimensions of the lower jaw and tongue, a stock of tongue blades, e.g. 3-6, each of which has a different length and width, is needed. A selected tongue blade is adapted to contact the tongue, so as to be retracted from the oral cavity and to be retained within the alveolar arch of the lower jaw. However, a selected tongue blade may not necessarily cover the entire tongue, and regions of the tongue protruding from the tongue blade tend to swell, remaining in the oral cavity and interfering with the surgical field. Due to this interference, the MG is liable to move, requiring readjustment of the various components thereof.
Tube protection: The tongue blade is liable to compress and obstruct the ventilation tube, particularly in the vicinity of the teeth. Body heat warms the tube, which consequently becomes soft and susceptible to collapse, bending and obstruction, often leading to disruption in the passage of air therethrough.
Ergonomics: Manipulation of the MG is cumbersome. The use of surgical instruments is additionally problematic, due to the configuration of components such as angles, protrusion, latch 21 and key 23 protruding from frame 5, resulting in the entanglement of suturing threads.
Illumination: An external upper surgical lamp and/or headlight are generally required. These types of illumination cast their light downward into the bottom of the oral cavity (posterior wall), and are difficult to control and direct into many of the dark upper and lateral oral recesses. Furthermore, shadows are cast from the surgical instruments and from the hands of the surgeon.
U.S. Pat. No. 4,024,859 discloses a mouth gag wherein the entire side member of the frame rotates, allowing a faster (but not safer) release and insertion, but otherwise suffers from all of the aforementioned drawbacks.
It is an object of the present invention to provide a surgical mouth gag which is easily and safely applied into and removable from, the oral cavity.
It is an object of the present invention to provide a surgical mouth gag which reduces the risk of potentially hazardous ventilation tube kink or displacement.
It is an additional object of the present invention to provide a surgical mouth gag to which the tongue blade may be set in an ergonomic position for introduction, use and removal.
It is a further object of the present invention to provide a surgical mouth gag in which all the retracting blades and their release is done in an ergonomic way.
It is yet another object of the present invention to provide a surgical mouth gag which prevents protrusion of the tongue around the tongue blade.
It is an additional object of the present invention to provide a surgical mouth gag which is configured such that suturing thread entanglement is precluded.
It is still another object of the present invention to provide a surgical mouth gag that will allow a good illumination to reach all oral recesses
It is yet an additional object of the present invention to provide a surgical mouth gag which overcomes the drawbacks of the prior art.
Other objects and advantages of the invention will become apparent as the description proceeds.